CVE-2023-51764
postfix - security update
Description
Postfix through 3.8.5 allows SMTP smuggling unless configured with smtpd_data_restrictions=reject_unauth_pipelining and smtpd_discard_ehlo_keywords=chunking (or certain other options that exist in recent versions). Remote attackers can use a published exploitation technique to inject e-mail messages with a spoofed MAIL FROM address, allowing bypass of an SPF protection mechanism. This occurs because Postfix supports <LF>.<CR><LF> but some other popular e-mail servers do not. To prevent attack variants (by always disallowing <LF> without <CR>), a different solution is required, such as the smtpd_forbid_bare_newline=yes option with a Postfix minimum version of 3.5.23, 3.6.13, 3.7.9, 3.8.4, or 3.9.
How to fix CVE-2023-51764
To remediate CVE-2023-51764, upgrade the affected package to a fixed version below.
- —upgrade to 3.5.23-0+deb11u1 or later
- —upgrade to 3.4.23-0+deb10u2 or later
Is CVE-2023-51764 being exploited?
Moderate — EPSS is 28.5%. Track this CVE but it's not at the top of the prioritisation list.
Affected packages (2)
- from 0, < 3.5.23-0+deb11u1
- from 0, < 3.4.23-0+deb10u2
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 3.1 | MEDIUM5.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N |